1. Field of the Invention
The present invention relates to a method of producing erythritol and more particularly to a method of producing erythritol that uses fermentation in a medium containing calcium and produces erythritol in an industrially advantageous manner.
2. Description of the Related Art
In methods of producing erythritol, there have been known a method in which the production is made by cultivating a yeast belonging to the genus Trigonopsis or the genus Candida in a medium containing glycerol as a carbon source and a casein hydrolysate as a nitrogen source (Japanese Examined Patent Publication No. Sho 47-41549), a method in which the production is made by cultivating a yeast belonging to the genus Candida, the genus Torulopsis, or the genus Hansenula in a medium containing a hydrocarbon or the like as a carbon source and yeast extracts or urea as a nitrogen source (Japanese Examined Patent Publication No. Sho 51-21072), and the like. However, these methods have not been yet industrialized since the raw materials used as the carbon source are unsuitable for practical productions on an industrial scale.
Also, there have been known a method in which the production is made by cultivating Moniliella tomentosa var pollinis in a medium containing a saccharide such as glucose as a carbon source (Japanese Laid-Open Patent Publication No. Sho 60-110295 and the like) and a method in which an erythritol-producing microorganism is cultivated in a medium containing yeast extracts and corn steep liquor as a nitrogen source (Japanese Laid-Open Patent Publication No. Hei 01-199584.
As the method of producing erythritol have been known various methods such as those described above. However, such known methods suffer much load on production process since glycerol is by-produced in large amounts or completion of fermentation (consumption of glucose) takes a long time, and are also economically disadvantageous.